Japanese clock

A Japanese clock (和時計, wadokei) is a mechanical clock that has been made to tell traditional Japanese time, a system in which daytime and nighttime are always divided into six periods whose lengths consequently change with the season. Mechanical clocks were introduced into Japan by Jesuit missionaries (in the 16th century) or Dutch merchants (in the 17th century). These clocks were of the lantern clock design, typically made of brass or iron, and used the relatively primitive verge and foliot escapement. Tokugawa Ieyasu owned a lantern clock of European manufacture.

Neither the pendulum nor the balance spring were in use among European clocks of the period, and as such they were not included among the technologies available to the Japanese clockmakers at the start of the isolationist period in Japanese history, which began in 1641. The isolationist period meant that Japanese clockmakers would have to find their own way without significant further inputs from Western developments in clockmaking. Nevertheless, the Japanese clockmakers showed considerable ingenuity in adapting the European mechanical clock technology to the needs of traditional Japanese timekeeping.